Continuous automatic liquid sampler

ABSTRACT

This invention concerns the continuous automatic sampling of a flowing fluid. The sampler comprises a number of bottles initially filled with an auxiliary fluid of lower density than the fluid to be sampled, and inert in relation to it; each bottle is connected to a central suction pump with an adjustable uniform flow-rate by an electro-valve controlled by a programmed clock, and each bottle is also fitted with a tube conveying liquid to it from a container forming part of a branch circuit from the main flow of liquid; this tube siphons the liquid into each bottle, and it contains an aperture above the maximum level reached by the sample fluid. The main applications of this invention are in the testing of factory effluents and canal and river pollution.

United States Patent 91 Audouze et al.

[111 3,896,673 [451 July 29,1975

1 CONTINUOUS AUTOMATIC LIQUID SAMPLER [76] Inventors: Bernard Audouze, Chateau Latapy a, Lagor (64); Guy Bonometti, 2, allee Nietce a, Mourenx, both of France [22] Filed: May 22, 1973 [21] Appl. No.: 363,176

[30] Foreign Application Priority Data 1 May 29, 1972 France 72.19128 [52] U.S. Cl 73/421 B [51] Int. Cl. G0ln 1/14 [58] Field of Search 73/421 R, 421 B, 422 R, 73/422 TC [56] References Cited UNITED STATES PATENTS 2,284,560 5/1942 Cornell 73/422 R 3,362,222 l/1968 Johnson et a1. 73/421 B 3,478,596 11/1969 Farrell, Jr 73/421 B 3,681,995 8/1972 Paatzsch 73/421 B Primary Examiner-S. Clement Swisher Attorney, Agent, or Firm-Burgess, Ryan & Wayne [57] ABSTRACT This invention concerns the continuous automatic sampling of a flowing fluid.

The sampler comprises a number of bottles initially filled with an auxiliary fluid of lower density than the fluid to be sampled, and inert in relation to it; each bottle is connected to a central suction pump with an adjustable uniform flow-rate by an electro-valve controlled by a programmed clock, and each bottle is also fitted with a tube conveying liquid to it from a container forming part of a branch circuit from the main flow of liquid; this tube siphons the liquid into each bottle, and it contains an aperture above the maximum level reached by the sample fluid.

The main applications of this invention are in the testing of factory effluents and canal and river pollution.

5 Claims, 2 Drawing Figures PATENTEDJULZBISYS 3, 896,673

SHEET 1 E 5 5 iii; 7 T5. I 3 8 CONTINUOUS AUTOMATIC LIQUID SAMPLER This invention concerns an apparatus designed to take an average sample of a flowing fluid.

Existing sampling systems usually function intermittently, and although the rate of sampling can be adjusted, it is not linked to the flow-rate of effluent to be sampled. A few continuous apparatuses exist but they use sampling systems in direct contact with the effluent, and are thus polluted by it, affecting the representative nature of the sample. The disadvantage of mechanical lifting devices using scoops. paddle wheels or Archimedes screws is that they disturb the sample and could encourage segregation.

The present invention overcomes these drawbacks, ensuring an average sample representing all of the fluid flowing past a given point within a given period without agitating the sample in any way, and without any contact between the fluid and the sampling system, thus removing the possibility of any residual pollution resulting from previous sampling operations and allowing the volume of samples and duration of sampling to be modified considerably, the samples to be kept at a particular temperature, and preventing any alteration in the sample by the addition or removal of fluid by a siphoning effect.

This apparatus to take continuous average samples of a flowing fluid comprises, on the one hand a number of bottles, initially filled with an auxiliary fluid, the density of which is lower than the fluid to be sampled, which will not mix with it or affect it in any way, and which occupies the upper part of each bottle during the filling operation. The upper part of each bottle is connected by a tube. ending above the maximum upper level to which the bottle is filled, to a suction pump with an adjustable uniform flow-rate, through an electro-valve controlled by a programmed clock. Each bottle is also connected by a siphon tube, ending at a point near the bottom of the bottle, to a container holding the fluid to be sampled. The container is fed by a pump with a uniform flow rate, which removes fluid from the channel through which it flows, and is continuously emptied back into this channel, downstream of the sampling point, through an overflow spout. Means are provided for subordinating the motor driving the suction pump to the readings of a flowmeter in the channel.

In one preferred embodiment, the tube conveying the sample of fluid from the central container to each bottle contains an aperture located above the maximum upper level reached by the sample of fluid.

According to another feature, each bottle is connected to the suction pump. through a separate electrovalve, and by a siphon tube to the container holding the fluid to be sampled.

According to another feature, samples can be collected in several bottles at once, by programmed simultaneous operation of the electro-valves connected to each of them.

It will be easier to understand the invention from the following description of one embodiment, illustrated by the accompanying drawings, wherein FIG. I is a schematic illustration of a sampling system in accordance with the invention; and

FIG. 2 is a top view of a portion of a preferred embodiment of the invention.

An apparatus such as the one shown in FIG. I contains a series of bottles (e.g. l and 2). placed for convenience in one or more concentric circles on a base (not shown here). In the centre of the circle or circles is a container 3, which is fed at a uniform rate by a pump 4 with fluid drawn from a point 5 in the channel 6 containing the fluid to be sampled. Container 3 has an overflow pipe 7, which discharges the fluid back into the channel, downstream of the sampling point.

Each of bottles is hermetically sealed with a stopper 8, through which p sses a filling tube 9, consisting of an upturned U-shaped tube, one arm of which goes into the container 3 while the other projects into the bottles 1 and 2 respectively to a point 10 one or two centimetres from the bottom. An aperture 11 is provided in each tube 9 beneath the bottle stopper and above the maximum level reached by the sample of fluid. The auxiliary fluid initially filling each bottle is sucked out, through a separate other pipe 12 passing through the bottom stopper, by a peristaltic pump 13, of the type in which flexible pipes are squeezed, for instance, with an adjustable uniform flow-rate. Each bottle is connected to a three-way electro-valve 14, one outlet leading to the pump 13, the second to the respective sample bottle, and the third allowing the pressure inside the bottle to be regulated to match the pressure prevailing above the fluid to be sampled, namely atmospheric pressure in the case of open-air channels.

Each electro-valve 14 is connected to a central control device 15, comprising an electronic clock 16 and means for selecting the sampling program 17.

The suction pump 13 is controlled by a mechanism 18, which subordinates it to the readings of a flowmeter l9, placed in the channel close to the sampling point 5. In this way, the rate of sampling is kept proportional to the flow-rate in the channel.

FIG. 2 represents part of the same apparatus seen from above, showing one half of a base containing twelve positions for bottles (e.g. 1), the central container 3, pipe 12 to suck out the auxiliary fluid, and three-way eIectro-valve 14.

Each of the bottles are enclosed in a casing (not shown) containing a heat-insulating material such as glass wool, so that if a refrigerating device is added, the temperature of the samples can be kept at 2 or 4C, which is essential for the biological protection and analysis of the samples.

Ifa number of bottles of the same sample are needed, another type of apparatus can be used, comprising groups of bottles, each group containing the number of bottles required for a sample. Each bottle in these groups has its own siphon tube and suction pipe connected to an electro-valve, and the electro-valves for each group are operated simultaneously, in accordance with a program selected at the central control point.

The apparatus operates as follows.

Bottles and pipes are placed in position, and the three-way electro-valves are adjusted to place the inside of each bottle in communication with the space above the channel of fluid to be sampled; in other words, if sampling takes place in the open air, and air is used as the auxiliary fluid in the bottles, the bottles and pipes will be at atmospheric pressure.

Another auxiliary fluid may be selected such as an inert gas or liquid of lower density than the fluid to be sampled. and which will not mix with it.

When the control system has been regulated to ensure the appropriate frequency of sampling, the sampling operation begins. The electro-valve for bottle n 1 connects it to the suction pump. A depression of a few millimetres of mercury draws fluid from the central container, after a few seconds delay. Throughout the operation, the rate of sampling remains proportional to the flow-rate of fluid in the channel so that the contents of the bottle are a representative average sample of the fluid flowing past during the period of sampling. When this period has elapsed, the control system disconnects bottle n 1 from the suction pump, and regulates the pressure in the bottle to match the pressure above the central container. The same operation begins immediately thereafter for bottle n 2.

In a'sampler with 24 bottles on a circular base, as partly illustrated in FIG. 2, the control system comprises two programs, for hourly or two-hourly sampling. Other programs can be added.

The flow-rate of the suction pump can be adjusted in various ways, either intermittently, by changing the diameter or number of the flexible pipes, or continuously, by regulating the speed of movement of the rollers. If the apparatus has been suitably assembled, the flow-rate can be adjusted by altering the diameter or number of pipes during sampling, while the other method is normally used when sampling is subordinated to readings from a flowmeter operating continu ously in the channel.

When stored, the samples are protected against any risk of further liquid entering or being siphoned off during storage, by the aperture on the sampling tube, be-

neath the bottle stopper and above the maximum level of the fluid samples.

With a programme involving simultaneous operation of equal groups of electro-valves, the number of identical samples obtained during one sampling operation is the same as the number of electro-valves in each group,

whereas division of a single sample would result in different sub-samples, because of the segregations that are bound to occur. This arrangement also allows suitable reagents to be placed in the bottles before sampling, in order to stabilize certain unstable components of the effluents, which it would otherwise be difficult to trace and analyse later.

What is claimed is:

1. An apparatus for continuously taking average samples of a fluid flowing in a channel, comprising a container for holding fluid to be sampled, pump means connected to feed fluid to be sampled at a uniform flow rate from a sampling point of said channel to said container, overflow spout means connected to empty fluid from said container back to said channel at a point below said sampling point in the direction of flow of fluid in said channel, a plurality of sampling bottles, an auxiliary fluid in said bottles, said auxiliary fluid having a density lower than the density of said fluid to be sampled and which will not mix with nor effect the fluid to be sampled in any manner, a suction pump having an adjustable uniform flow rate, tube means connected between said suction pump and the upper portion of each bottle, said tube means terminating above the maximum upper level to which the respective bottle is to be filled during a sampling operation. electro-valve means connectedto control flow of fluid in said tube means, programmed clock means connected to control said electro-valve ,means, and separate siphon tubes connecting each of said bottles. at a point near the bottom thereof. to said container, whereby suction applied to each bottle during a filling operation draws fluid to be sampled from said container to the respective bottle. and the auxiliary fluid in the respective bottle consequently occupies the upper portion of the respective bottle.

2. The apparatus of claim 1 wherein the siphon tube connected between each said bottle and said container has an aperture above the maximum upper level reached by a sample of fluid in each said bottle.

3. The apparatus of claim 1 wherein each said bottle is connected to said suction pump by a separate electro-valve in the respective tube means, and each said bottle is connected to said container by a separate siphon tube.

4. The apparatus of claim 1 wherein said programmed clock is connected to simultaneously control a plurality of electro-valves for simultaneously collecting average samples of said fluid to be sampled in a plurality of said bottles. I

5. An apparatus for continuously sampling a fluid flowing in a channel, comprising a container for holding the fluid to be sampled, pump means for continuously directing fluid from a sampling point of said channel to said container at a uniform rate, overflow means for feeding back fluid from said container to said channel at a point below said sampling point in the direction of flow of fluid therein for maintaining the level of fluid in said container, a plurality of sealed bottles, suction pump means, a separate electro-valve for each said bottle, tube means connecting the upper portion of each said bottle by way of the respective clectro-valve to said suction pump means, separate siphon means coupled between the bottom portion of each said bottle to said container, such siphon means having apertures above the maximum level within each bottle to which the respective bottle is to be filled during'a sampling operation, and an auxiliary fluid in each bottle, said auxiliary fluid having a density less than the density of said fluid to be sampled and being immiscible with and chemically inert with respect to said fluid to be sampled.

UNITED STATES PATENT OFFICE CERTIFICATE OF QORRECTION Patent No. 3,896,673 Dated Ju y 29, 1975 lnventofls) Bernard Audouze, et a1 It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

On the face of the above document please add the assignment information which is as follows:

-Societe Nationale Des Petroles D'Aquitaine- Signed and Scaled this [SEAL] Arrest:

RUTH C. MASON C. MARSHALL DANN Allesting Officer Commissioner of Parents and Trademarks twentieth D f January I 976 

1. An apparatus for continuously taking average samples of a fluid flowing in a channel, comprising a container for holding fluid to be sampled, pump means connected to feed fluid to be sampled at a uniform flow rate from a sampling point of said channel to said container, overflow spout means connected to empty fluid from said container back to said channel at a point below said sampling point in the direction of flow of fluid in said channel, a plurality of sampling bottles, an auxiliary fluid in said bottles, said auxiliary fluid having a density lower than the density of said fluid to be sampled and which will not mix with nor effect the fluid to be sampled in any manner, a suction pump having an adjustable uniform flow rate, tube means connected between said suction pump and the upper portion of each bottle, said tube means terminating above the maximum upper level to which the respective bottle is to be filled during a sampling operation, electro-valve means connected to control flow of fluid in said tube means, programmed clock means connected to control said electro-valve means, and separate siphon tubes connecting each of said bottles, at a point near the bottom thereof, to said container, whereby suction applied to each bottle during a filling operation draws fluid to be sampled from said container to the respective bottle, and the auxiliary fluid in the respective bottle consequently occupies the upper portion of the respective bottle.
 2. The apparatus of claim 1 wherein the siphon tube connected between each said bottle and said container has an aperture above the maximum Upper level reached by a sample of fluid in each said bottle.
 3. The apparatus of claim 1 wherein each said bottle is connected to said suction pump by a separate electro-valve in the respective tube means, and each said bottle is connected to said container by a separate siphon tube.
 4. The apparatus of claim 1 wherein said programmed clock is connected to simultaneously control a plurality of electro-valves for simultaneously collecting average samples of said fluid to be sampled in a plurality of said bottles.
 5. An apparatus for continuously sampling a fluid flowing in a channel, comprising a container for holding the fluid to be sampled, pump means for continuously directing fluid from a sampling point of said channel to said container at a uniform rate, overflow means for feeding back fluid from said container to said channel at a point below said sampling point in the direction of flow of fluid therein for maintaining the level of fluid in said container, a plurality of sealed bottles, suction pump means, a separate electro-valve for each said bottle, tube means connecting the upper portion of each said bottle by way of the respective electro-valve to said suction pump means, separate siphon means coupled between the bottom portion of each said bottle to said container, such siphon means having apertures above the maximum level within each bottle to which the respective bottle is to be filled during a sampling operation, and an auxiliary fluid in each bottle, said auxiliary fluid having a density less than the density of said fluid to be sampled and being immiscible with and chemically inert with respect to said fluid to be sampled. 